Advertiser: Pacific Bell Agency: D'Arcy Masius Benton & Bowles, St. Louis Challenge: Convince privacy-conscious Californians that caller ID has advantages. The Ads: PacBell uses humor in four television commercials for caller ID, a service that displays a caller's phone number (and the identity of the person assigned the number) on a special screen when the phone rings. Three of the ads revolve around a medieval knight who opens the castle door without checking to see who's knocking.

Last year, executives at the ad firm D'Arcy Masius Benton & Bowles saw the potential for growth in Los Angeles. So they moved the agency's West Coast headquarters to new offices on the 10th floor of a Wilshire Boulevard high-rise. Its a good thing the 11th floor was empty, too. The agency, which landed the $29-million NBC network advertising account last week, has already started to fill up the building's 11th floor.

A change of ownership has brought massive expansion plans at Krause's Sofa Factory, a privately held, Fountain Valley-based chain that wants to quadruple its size nationally to about 200 retail showrooms. Krause has a 1987 sales goal of $90 million and plans to add 150 outlets within the next five to 10 years, Doug Vunder, vice president of retail operations, said last week.

Cadillac Fairview Corp. of Toronto, one of North America's largest publicly held commercial real estate developers, has established its entity for metropolitan Los Angeles at the newly completed 6500 Wilshire office tower. Developed by Dallas-based Cadillac Fairview Urban Development Inc., the $100-million, 23-story tower at Wilshire and San Vicente boulevards has become this subsidiary's U.S.

Advertising agencies Benton & Bowles Inc. and D'Arcy MacManus Masius Worldwide said Monday that they are joining to create the nation's fifth-largest advertising agency in what will be the industry's largest merger. Following a pattern of industry consolidation, the companies will form an agency that will be known as D'Arcy Masius Benton & Bowles Inc. and will have 6,000 employees and $2.47 billion in annual billings. It will rank sixth internationally, with offices in 50 cities worldwide.

The parent companies of two big advertising agencies that represent such major clients as Procter & Gamble, Coca-Cola and General Motors are merging to create a global new agency with more than $1.7 billion in revenue. Chicago-based Leo Group and New York-based MacManus Group, which own Leo Burnett Co. and D'Arcy Masius Benton & Bowles, are merging into a new company that initially will be called BDM. The Chicago-based company will become the world's fourth-largest advertising company.

Pepsi is about to give glasnost a taste of Madison Avenue razzmatazz. Forget those Pepsi commercials that featured Michael Jackson moonwalking and Michael J. Fox rain dancing. This week, the soft drink giant's New York advertising agency has sent a crew of 23 to Moscow to film a flashy Pepsi spot--portions of which will be filmed at Red Square. By jetting halfway around the globe to film this ad, literally, in Mikhail S.

Sandra Corbet, 51, advertising executive who produced television and print commercials. Raised in Brooklyn, Corbet graduated from City College of New York and had homes in Manhattan and Los Angeles. She produced commercials for such agencies as D'Arcy Masius Benton & Bowles, Young & Rubicam and Kirschenbaum & Bond. She also produced ads for Creative Artists Agency and Coca-Cola.

In one of the biggest advertising deals this year, Century 21 Real Estate Corp. on Tuesday awarded its $30-million national account to Minneapolis-Advertising, dropping incumbent McCann-Erickson/Los Angeles. The decision to split with the agency, which had the account for seven years, is a blow to the local advertising market because it pulls a trophy account and major piece of business out of Southern California.